Known kneader machines for both domestic and industrial use, comprise a container, typically made of stainless steel, wherein a rotor rotatably restrained to a shaft of an electric motor is arranged, the rotor being provided with a plurality of mixing paddles.
In order to make an alimentary dough, a predefined amount of ingredients in a solid form, such as mixtures of flour and/or meals, is poured into the container and continuously mixed by rotating the rotor paddles during the preparation of the dough. In the case of alimentary doughs for bread or confectionery products, the ingredients in a solid form also comprise yeast.
During the mixing step, the container is usually sealed by a lid and ingredients in a liquid form, e.g. water, necessary to prepare the desired dough are gradually added to the ingredients in a solid form. The mixing step lasts until a homogeneous dough suitable to be further processed is obtained.
It is known that an alimentary dough plays a very important role because its physical, chemical and structural properties determine the quality of a finished product obtained therefrom. The subsequent processing steps in fact may only optimize the finished product in relation to the initial properties of the dough, but it is not possible to improve the properties of the initial dough, nor to correct any limits and imperfections e.g. due to a poor quality of its ingredients or to a preparation mode that is not correct.
It is also known that the formation of an alimentary dough starts with the addition of water to a mixture of flour and/or meals. Water may be added either directly or indirectly as part of liquid ingredients such as eggs. In order to obtain an optimal hydration of the dough, ideally every single particle of the mixture of flour and/or meals should be wetted so as to receive an amount of water proportional to its mass.
The hydration of the particles of the mixture of flour and/or meals triggers a series of chemical and physical processes leading to the formation of gluten. During mixing and kneading, the molecules of gluten form a series of chemical bonds that make the alimentary dough more and more compact and elastic.
It is known that compactness and elasticity of an alimentary dough are highly influenced by the hydration level of the particles of mixtures of flour and/or meals. In order to promote the hydration of the particles of mixtures of flour and/or meals it is used to inject the liquid ingredients into the container in the form of sprays.
Patent GB 190826 discloses for example a kneader comprising a container inside which a rotor having an horizontal axis and provided with a plurality of mixing arms is rotatably arranged. The kneader also comprises a reservoir suitable to contain water, oil or other liquid ingredients. Mixtures of flours and/or meals necessary to make a dough are introduced into the container through a supply duct equipped with a vibrating device and ending with an aperture formed in a lid of the kneader. Therefore, the mixtures of flours and/or meals enter the container by gravity in a finely divided form as a result of the vibrations produced by the vibrating device. Since nozzles are arranged in the lid of the kneader, the particles of the mixtures of flours and/or meals come into close contact with the liquid ingredients injected by the nozzles before reaching the bottom of the container and being mixed by the rotor, thus allowing to obtain an adequate hydration level. Thanks to these features, the kneader allows to reduce the mixing time of doughs.
The Italian patent application MI2009A001318, in the applicant's name, discloses a kneader for alimentary doughs, comprising a container provided with a tight lid, inside which a rotor having a vertical axis and provided with a plurality of mixing paddles is arranged. The kneader also comprises a plurality of nozzles restrained to the lid and suitable to the inject ingredients necessary to make an alimentary dough, such as water and eggs, into the container in the form of a spray. The vertical axis rotor is configured so as to generate a raising effect of the flour from the bottom of the container towards the lid, thus promoting the contact between the flour and the spray-injected ingredients, whereby it is possible to obtain very homogeneous and elastic doughs in mixing in times shorter than those achievable by the kneaders known in the art.
The homogeneity and compactness of the alimentary doughs are of fundamental importance not only in the field of pasta, but also in the field of bread and confectionery products, there being more and more felt the need to reduce mixing times in order to limit undesired overheating phenomena that generally trigger leavening.